效果图

  最近买了郭霖郭大神的书——第一行代码，正在学习，学到了kotlin中ListView的使用，特此记录一下，效果如下：

例子下载

https://download.csdn.net/download/ljp345775/12450945

代码实现

1. 首先编写listView需要的item的布局item.xml ，代码如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="wrap_content"android:orientation="horizontal"android:padding="5dp"><ImageViewandroid:id="@+id/iv_item_lv"android:layout_width="50dp"android:src="@drawable/apple_pic"android:layout_height="50dp" /><TextViewandroid:id="@+id/tv_item_lv"android:layout_width="wrap_content"android:layout_height="match_parent"android:layout_marginStart="10dp"android:gravity="center_vertical"android:text="apple"android:textSize="20dp" /></LinearLayout>

效果如下：

2. 编写listview的适配器adapter，代码如下：

import android.content.Context
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.BaseAdapter
import android.widget.ImageView
import android.widget.TextView
import com.example.kotlindemo1.R
import com.example.kotlindemo1.beans.Fruit/*** @作者： ljp* @时间： 2020/5/23 8:46* @描述：Listview 的 适配器**/
class ListAdapter(val context: Context, var data: List<Fruit>) : BaseAdapter() {override fun getView(position: Int, convertView: View?, parent: ViewGroup?): View {val vh: ViewHolderval view: Viewif (convertView == null) {view = LayoutInflater.from(context).inflate(R.layout.item1, parent, false);vh = ViewHolder(view)view.tag = vh} else {view = convertViewvh = view.tag as ViewHolder}//填充数据var fruit = getItem(position)if (fruit != null) {vh.iv_item_lv.setImageResource(fruit.ImgId)vh.tv_item_lv.text = fruit.name}return view}inner class ViewHolder(v: View) {val tv_item_lv: TextView = v.findViewById(R.id.tv_item_lv)val iv_item_lv: ImageView = v.findViewById(R.id.iv_item_lv)}override fun getItem(position: Int): Fruit {return data.get(position)}override fun getItemId(position: Int): Long {return position.toLong()}override fun getCount(): Int {return data.size}
}

3. 主界面中布局代码如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".activity.ListViewActivity"><ListViewandroid:id="@+id/lv"android:layout_width="match_parent"android:layout_height="match_parent"/></LinearLayout>

4. activity中的代码如下：

package com.example.kotlindemo1.activityimport androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.AdapterView
import android.widget.Toast
import com.example.kotlindemo1.R
import com.example.kotlindemo1.adapter.ListAdapter
import com.example.kotlindemo1.beans.Fruit
import kotlinx.android.synthetic.main.activity_listview.*class ListViewActivity : AppCompatActivity(), AdapterView.OnItemClickListener,AdapterView.OnItemLongClickListener {private lateinit var adapter: ListAdapterprivate var data = ArrayList<Fruit>()override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)setContentView(R.layout.activity_listview)supportActionBar?.title = "ListView"initData()adapter = ListAdapter(this, data)lv.adapter = adapter/*** 这是一种写法，还有下面一种写法*/
//        lv.setOnItemClickListener { parent, view, position, id ->
//            Toast.makeText(
//                this,
//                "你点击了->" + data[position].name,
//                Toast.LENGTH_SHORT
//            ).show()
//        }
//        //注意 item LongClick事件，有返回值
//        lv.setOnItemLongClickListener { parent, view, position, id ->
//            Toast.makeText(
//                this,
//                "你长按了->" + data[position].name,
//                Toast.LENGTH_SHORT
//            ).show()
//            true
//        }lv.setOnItemClickListener(this)lv.setOnItemLongClickListener(this)}//list view的item的点击事件override fun onItemClick(parent: AdapterView<*>?, view: View?, position: Int, id: Long) { Toast.makeText(this,"你点击了->" + data[position].name, Toast.LENGTH_SHORT).show()}//listview的item 的长按时间override fun onItemLongClick(parent: AdapterView<*>?,view: View?, position: Int,id: Long ): Boolean {Toast.makeText(this,"你长按了->" + data[position].name,Toast.LENGTH_SHORT).show()return true}private fun initData() {repeat(2) {data.add(Fruit("apple", R.drawable.apple_pic))data.add(Fruit("banana", R.drawable.banana_pic))data.add(Fruit("orange", R.drawable.orange_pic))data.add(Fruit("watermelon", R.drawable.watermelon_pic))data.add(Fruit("pear", R.drawable.pear_pic))data.add(Fruit("grape", R.drawable.grape_pic))data.add(Fruit("pineapple", R.drawable.pineapple_pic))data.add(Fruit("strawberry", R.drawable.strawberry_pic))data.add(Fruit("cherry", R.drawable.cherry_pic))data.add(Fruit("mango", R.drawable.mango_pic))}}
}